Filtration Strategies for Proactive Maintenance: A Guide to Optimal Filter Placement

Filtration Strategies for Proactive Maintenance: A Guide to Optimal Filter Placement

Filtration Strategies for Proactive Maintenance: A Guide to Optimal Filter Placement

Three Key Steps to Proactive Care

Implementing proactive maintenance involves three key steps:

1. Setting cleaning goals,
2. Implement specific actions to achieve these goals,
3. Measuring pollutant levels regularly.

This post takes an in-depth look at step two, with a particular focus on how to choose the most effective filter position to support contamination control.

The Importance of Filter Position

Once cleanliness goals are set, engineers are faced with the challenge of optimizing filter placement that spans multiple locations. Choosing the right filter location is a critical step to best manage contaminant ingress and removal, while balancing accessibility, system performance, and cost-effectiveness.

To ensure an effective input balance, engineers must consider:

• Whether the filter will be used for protection or contamination control,
• Ease of access for maintenance,
• Performance to meet the requirements of the targeted cleanliness levels.

Protection-Oriented Filtration Strategies

The first decision point is whether the system needs to protect sensitive components. The use of a protection filter is recommended, especially in main hydraulic systems that work with precision servo valves with clearances of less than 5 microns.

The main features of protection filters:

• Placed before sensitive components, it protects against contaminants, usually from the tank or pump.
• Since it is designed to operate under high pressure, it requires more powerful and costly structures.
• It usually does not include a bypass valve; This means that if the filter becomes clogged, the system will shut down.
• These filters are for protection purposes only, they are not used to ensure general system cleanliness.

Filtration to Maintain Cleaning Goals

The first step is to map solid particle entry points throughout the system. The goal is to select a filter that compensates for particle input and a position that matches it.

The entry points are:

• Pollution after installation and service work,
• Environmental contamination,
• Entrance through ventilation holes and hatches,
• Particles leaking from gaskets and seals,
• Contaminants from work surfaces and lubricants.

The basic equation here is:
Removal Rate > Sum of Ingested and Produced Pollutants

Note: The cost of preventing dirt from entering the system is much lower than removing it later. That's why reducing system-wide entries should always be a priority.

Filter Location Options

Depending on the type and complexity of the system, different filter positions should be evaluated:

1. Suction Line Filtration
• It holds large foreign objects.
• Generally, 100 micron strainers are used.
• Filters that are too fine can lead to cavitation.
2. Pressure Line Filtration
• It provides effective protection for sensitive components and the entire system.
• The filter must withstand full system pressure.
• It requires a design that is resistant to pressure changes.
3. Return Line Filtration
• It prevents contaminants from reaching the tank.
• It is more cost-effective and easy to install.
• It does not provide direct protection to sensitive components.
4. Off-Line Filtration
• Filter replacement can be done without shutting down the system.
• It provides continuous improvement in liquid cleaning.
• The installation cost is higher because it requires extra pumps and piping.
5. Bypass Filtration
• It is often used in engines.
• It filters out a small portion of the stream, resulting in finer filtration.
• It is a cost-effective alternative.

Multiple Types of Pollutants and Advanced Applications

Filtration is not only about solid particles; It should also cover other contaminants such as water, varnish and oxidized oils. For this reason, offline vacuum dehydration and oil molecule cleaning units should also be considered, especially in systems that have experienced varnish problems in the past.

Bypass filtration supports pressure line filtration, allowing for finer filtration without damaging sensitive components.

Considerations for Smart Filter Placement

• The main purpose of the filter is to balance the proportion of contaminants entering the system.
• With proactive maintenance strategies, the input rate should be reduced and thus the life of the filter should be extended.
• Filters should be easily accessible, and blockages should be monitored with a pressure difference monitoring device.
• It should be designed to keep system performance and maintenance times to a minimum.